NTuple is a Python module used by high-energy physicists and astrophysicists to easily and efficiently access ntuple data stored in large ROOT data stores. Specifically, NTuple provides a friendly Pythonic interface to TNtuples and TTrees stored in TFiles

Omseek has been renamed to Xapian. Xapian is a Search Engine Library, written in C++ with bindings for Perl, Python, PHP, Java, Tcl, C# and Ruby. It allows you to easily add advanced indexing and search facilities to your applications. See xapian.org

Open-GMF is an open Ground Water Modeling Framework for hydrogeologists and reservoir engineers. It is an extensible development environment for finite-difference, finite-element, and finite-volume models tailored to specific problems.

PGP Individual UID Signer makes signing all the UIDs on all of the keys at a PGP Keysigning party much simpler. It prompts for verification fingerprints, and then signs each UID on each key separately and PGP/Mime encrypt-emails them to their recipient.
NOTE: Developement now happens at GitHub: http://github.com/jaymzh/pius

Papaya is a fully featured MUD client with features including ANSI colour, multiple simultaneous connections, proxy support, aliases, triggers and plugins. It uses the GTK widget set and runs on (at least) Linux, Windows, FreeBSD, Solaris and MacOSX.

PyCarge is a cross-platform opensource console style RPG engine written in Python. It has a built-in character and map editor. RPGMaker-like macros ~and~ full scripting cabilities are included. Allows custom character and tileset sizes.